/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.table.runtime.operators.sink.constraint;

import org.apache.flink.annotation.Internal;
import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
import org.apache.flink.table.data.RowData;
import org.apache.flink.table.runtime.operators.TableStreamOperator;
import org.apache.flink.table.runtime.util.StreamRecordCollector;

/**
 * Processes {@link RowData} to enforce the following constraints:
 *
 * <ul>
 *   <li>{@code NOT NULL} column constraint of a sink table
 *   <li>{@code CHAR(length)}/@{code VARCHAR(length)}: trim string values to comply with the {@code
 *       length} defined in their corresponding types.
 * </ul>
 */
@Internal
public class ConstraintEnforcer extends TableStreamOperator<RowData>
        implements OneInputStreamOperator<RowData, RowData> {

    private static final long serialVersionUID = 1L;

    private final String operatorName;
    private final ConstraintEnforcerExecutor executor;

    private transient StreamRecordCollector<RowData> collector;

    public ConstraintEnforcer(ConstraintEnforcerExecutor executor, String operatorName) {
        this.executor = executor;
        this.operatorName = operatorName;
    }

    @Override
    public String getOperatorName() {
        return operatorName;
    }

    @Override
    public void open() throws Exception {
        super.open();
        collector = new StreamRecordCollector<>(output);
    }

    @Override
    public void processElement(StreamRecord<RowData> element) throws Exception {
        RowData processedRowData = executor.enforce(element.getValue());
        if (processedRowData != null) {
            collector.collect(processedRowData);
        }
    }
}
